002643   KARNATAK G, BISHT P S, NEGI O P S (Physics Dep, K.U.S.S.J. Campus, Almora , Uttarakhand, Email: gauravkarnatak2009@yahoo.in) : Quaternionic formalism for non-Abelian gauge theory of dyons and gravito-dyons. J Mountain Res 2019, 14(1), 31-3.

Starting with the Quaternion formulation of SU(2)xU(1) gauge theory of dyons and gravitodyons, it is shown that the formulation characterizes the Abelian and non-Abelian gauge structure of dyons and gravito-dyons in terms of purely real and imaginary units of quaternion.

7 ref

002654   MAMGAIN A, UPADHYAY T C (Physics Dep, H.N.B. Garhwal Univ, Srinagar (Garhwal) 246174 Uttarakhand, Email: anubhuti.mamgain01@gmail.com) : Changes in ferroelectric properties of MASD alum along with temperature by using PLCM model. J Mountain Res 2019, 14(2), 37-45.

With addition of third-and fourth-order phonon anharmonic interactions, and extra spin-lattice interaction term into pseudospin-lattice coupled mode (PLCM) model, MASD alum has been studied. Employing double time temperature dependent Green′s function technique expressions for shift and width of response function, normal mode frequency, dielectric constant and loss stangent have been derived for MASD alum. Numerical calculation has been done. Theoretical results have been compared with experimental results of Pepinsky et al. [16]. A good agreement has been found.

3 illus, 1 table, 26 ref

002653   LILY M K, BHATT K K, KUMAR L, DANGWAL K (Science Dep, Modern Institute of Technology (MIT), Rishikesh-249201, Uttarakhand, Email: kdangwal1@yahoo.co.in) : The study of growth kinetics of Bacillus subtilis BMT4i (MTCC 9447) using mobil oil as the sole carbon and energy source. J Mountain Res 2019, 14 (2), 1-8.

The present study demonstrated the growth kinetics of a potent high molecular weight polycyclic aromatic hydrocarbon (HMW-PAH) degrader Bacillus subtilis BMT4i (MTCC 9447) using mobil oil or engine oil as the sole carbon and energy source. The study was performed to demonstrate the variations in morphology and growth kinetics in benzo-a-pyrene (BaP) degrading BMT4i due to the mobil oil induced stress conditions. The morphological variations were evaluated using Gram staining and spore staining (Schaeffer-Fulton method) followed by assessment of viability and growth using colony forming units (CFU)/ml method by means of growing Bacillus subtilis BMT4i in basal salt medium (BSM) with mobil oil (2 %: BSMM) as sole carbon and energy source at different time intervals. The findings represented that mobil oil has noticeable effect on the shape and size of BMT4i cells. After 24 h of exposure to mobil oil, maximum BMT4i cells entered in to endospore development and several exospores were released after 24 h. The growth kinetics depicted an exponential increase in BMT4i cells in BSMM with increase in incubation time up to 3 days accomplishing maxima of 2.1 x 10¹⁹ demonstrating approx. 2x10¹¹ -fold enhancements in cell number and afterwards cell number declined. Increase in CFU number (approx. 2x10¹¹ fold) was directly linked with the BMT4i potential to use mobil oil as the sole carbon and energy source leading to elevation in cell number within just 3 days. Thus, it could be concluded that Bacillus subtilis BMT4i (MTCC 9447) is very competent in using mobil oil as the sole source of carbon and energy and hence it could be employed for bioremediation of mobil oil and PAH contaminated sites.

4 illus, 23 ref

002629   DUMBRAVA V, PAGODINAS D, KNYVA V, KUPCIUNAS I, CINCIKAS G, NOREIKA A, SIAUDINYTE L (Kaunas Univ of Technology, Kaunas, Lithuania) : Simplified and accelerated method of Led lamp useful life estimation. Mapan - J Metrol Soc India 2019, 34(2), 169–78.

LED lamps have experienced growth of usage in artificial lighting because of their high luminous efficiency, long lifetime and resistance to mechanical stresses. Many new manufacturers are starting to produce such lamps, and a part of them do not have enough experience in this particular field. This leads to cheap products that do not meet the product-specific requirements. Due to this reason, a study was initiated in order to analyze standards governing LED light sources, and the simplified and accelerated method for evaluation of lumen maintenance life of LED lamps was proposed. In this paper, the initial results of lamp temperature parameters, the AC/DC converter efficiency analysis and the experimental results of measurement and calculation of lumen maintenance life L₇₀ by applying the proposed technique are discussed.

27 ref

002617   ALI R S M, RAOUF M H A (Electrical Quantities Metrology Dep, National Institute of Standards, Giza, Egypt) : New method for measurement of AC voltages above 1 V using TVC and voltage divider. Mapan - J Metrol Soc India 2019, 34(2), 267–71.

In this paper, a new method is introduced for AC voltage ranges that are higher than 1 V by using the thermal converters. It can be used in laboratories in case of unavailability of the whole ranges of multiplier range resistors set. The introduced method depends on dividing the AC voltage of the unit under test to 1 V by using AC voltage divider. The divided AC voltage is then measured using 1 V thermal converter. The measured AC voltages are 10 V and 30 V at different frequencies. The expanded uncertainty is evaluated for the measurement results. The presented method is evaluated by comparing its obtained results and the results obtained by using the conventional thermal voltage converter, which consists of multiplier resistors, with the actual values of the AC voltages. The comparison proves that the new method is reliable and dependable for accurate measurements of AC voltages.

11 ref

002667   SINGH R, NAGLA K S (National Institute of Technology, Jalandhar, Punjab) : Sonar sensor model for the precision measurement to generate robust occupancy grid map. Mapan - J Metrol Soc India 2019, 34(2), .

Precise measurement of the parameters such as position and angular coordinates, distance travelled, and velocity and acceleration of an autonomous mobile robot in occupancy grid map is an active area of research. The stated parameters rely on the probability values stored in the grid cells of the occupancy grid. Occupancy grid mapping is a proficient paradigm in the field of mobile robotics for modeling the environment by receiving the sensory information from range sensors. The objective of this study is to develop novel approach—adaptive sonar model (ASM)—for the generation of robust occupancy grid by reducing the effect of inconsistency in the grid cells probabilities of the occupancy as a consequence of long-range measurement. The results acquired with the implementation of the ASM techniques are compared with the conventional sonar sensor model which reveals 20% reduction in the uncertainty in the occupancy grid map generated due to long-range measurement.

20 ref

002620   BALLAL M S, WATH M G (Electrical Engineering Dep, Visvesvaraya National Institute of Technology, Nagpur, Maharastra) : Current transformer accuracy improvement by digital compensation technique. Mapan - J Metrol Soc India 2019, 34(2), 225–37.

Measurement current transformers (CTs) are extensively used for measurement of energy by power distribution utilities. In this paper, current transformer error compensation unit (CTECU) is developed which is specially intended for providing compensation to all types of measurement CTs. The proposed CTECU is based on determination and application of correction coefficients, which are computed by the ratio and phase angle errors data. Analytical foundation is effectively expressed along with the development of CT error compensation algorithm. CTECU is implemented online in laboratory on 1.0 class and 0.5 class of CTs. The experimental performance is found satisfactory under various operating conditions. The novelty of the proposed algorithm is that it is possible to make conversion of CTs from one class to another class.

31 ref

002659   NAVALKAR V, SINGH K P, PRESS M (Centre for Excellence in Basic Sciences, Vidyanagari Campus, Santacruz (E), Mumbai 400 098, Email: tifr.vinita@gmail.com) : Thermal shaping of thin glass panels for hard X-ray telescope optics. J Astrophys Astr 2019, 40(3), 24.

We present a process for thermal forming of thin glass panels of borosilicate glass to produce mirror segments for X-ray telescope optics. The mirror segments are required to be shaped in a parabolic and hyperbolic shape in accordance with Wolter-I type design of X-ray telescope optics. Thermal forming of glass is a low-cost method to produce light-weight mirror segments. The process makes use of a semi-cylindrical quartz mold having surface roughness of the order of 1 nm. Flat glass sheets of 0.2 mm and 0.3 mm thickness are placed on the diametric edges of the mold. With a suitable thermal cycle, the glass sheets are thermally formed as per the shape of the mold. The shape of these formed glass sheets was measured using a non-contact optical setup. The surface quality measurements of the formed glass sheets were performed using atomic force microscope and they were found to be in the range of 0.04–0.33 nm. Once tested for acceptance, these glass sheets are coated using sputter deposition of multi-layers of high and low atomic number materials for hard X-ray reflection. Such mirror segments do not require polishing of the surface before being coated with multi-layers.

26 illus, 2 table, 25 ref

002650   KUMAR R, RAB S, PANT B D, MAJI S, MISHRA R S (CSIR-National Physical Laboratory, Delhi -110012) : FEA-based design studies for development of diaphragm force transducers. Mapan - J Metrol Soc India 2019, 34(2), 179–87.

This paper discussed the finite element analysis (FEA)-based design considerations and its role in finding optimum location of sensing element in diaphragm-based force transducers. The design studies of two diaphragms made of two different materials steel (EN 24) and silicon are discussed as per the analytical expressions available and further validated using FEA for values of deflection, stress and strain of the spring element with appropriate location for fixing of strain gauges so as to get the optimum output in electrical units in mV/V against the applied force. The proposed analytical study in conjunction with finite element analysis shall be indispensable in design and development of diaphragm-based force traducers of optimum electrical output for different industrial applications and also could be used as force transfer standard to disseminate the measurement traceability chain in force measurements throughout the country. The metrological investigation revealed that the measurement uncertainty is 0.06% for steel force transducer and 0.22% for silicon diaphragm force transducer.

19 ref

002666   SHEHATA A B, YAMANI R N, TAHOUN I F (National Institute of Standards, Giza-12211, Egypt) : Intra- and interlaboratory approach for certification of reference materials for assuring quality of low-alloy steel measurement results. Mapan - J Metrol Soc India 2019, 34(2), .

Certified reference materials are versatile tools to support quality, correctness and credibility of measurement results. They are used to provide the traceability of the measurement results to the SI unit. In the present work, seven low-alloy steel reference materials were developed by the National Institute of Standards, Egypt. Homogeneity of the developed reference materials (RMs) was studied by X-ray fluorescence spectrometer (XRF) and atomic emission spectrometer, and the results proved that the produced RMs were homogeneous enough for establishing traceability of measurement results and internal and external quality control schemes. Characterization of reference materials composition was performed by four independent analytical methods: gravimetry, XRF, optical emission and atomic absorption spectrometry in different laboratories. The assigned values of the mass fractions of the various elements of the alloys and their associated uncertainty were calculated by the weighted mean approach.

25 ref

002628   DOMÍNGUEZ-MANCERA B, RODRÍGUEZ-ANDRADE A , BARRIENTOS-MORALES M , CERVANTES-ACOSTA P , ZAMORA-PARDO A D, HERNÁNDEZ-BELTRÁN A H (Veracruz Univ, Veracruz, Mexico, Email: beldominguez@uv.mx) : Ghrelin and Leptin increase voltage-gated Na⁺ and Ca²⁺ currents in the RIN-m5f insulin-producing cell line. Indian J Biochem Biophys 2019, 56(3), 193-204.

β-pancreatic islet cells generate action potentials (AP) spontaneously or in response to different stimuli. This is orchestrated by the activity of diverse voltage-gated ion channels in the plasma membrane. Therefore, metabolic signals that modify the functional expression of these channels may alter β-cells excitability and in consequence the secretion of insulin. In particular, two hormones that regulate the voluntary food intake, Ghrelin and Leptin, may affect glucose serum concentrations by altering plasma insulin release. In this work, we use the insulin-producing RIN-M5f cell line to study the effects of the chronic treatment with Ghrelin or Leptin on the functional expression of voltage-gated Na⁺ and Ca²⁺ channels. Cells were kept in culture and then subjected to patch-clamp electrophysiology. Our results show that chronic incubation with Ghrelin or Leptin (10 nM, 72 h) increased the frequency of the spontaneous APs and the macroscopic current density through Na⁺ and Ca²⁺ channels. The analysis of the components of the Ca²⁺ currents showed that Ghrelin and Leptin differentially increased low- and high-threshold channels without causing apparent changes in current kinetics. The study of the electrophysiological mechanisms in insulin-secreting cells associated with the effects of Ghrelin and Leptin may shed light on the molecular processes involved in the endocrine/metabolic balance.

5 illus, 2 tables, 51 ref

002641   KALITA D, CHETIA L, CHETRI P, AHMED G A (Physics Dep, Tezpur Univ, Napaam 784028, Email: kalitadeb@gmail.com) : Investigation of structural and luminescence properties of nanocrystalline tungsten-incorporated molybdenum disulphide ternary compounds: An experimental and DFT study. Bull Mater Sci 2019, 42(3), 134.

The present manuscript reports the synthesis of tungsten-incorporated molybdenum disulphide ternary compounds in particle form at the nanoscale using existing solid state reactions, followed by ultrasonication and a density functional theory (DFT) investigation of the compound system. The effect of W in the W-inserted MoS2 ternary compound system is the subject of current research. A comparative study shows enhanced photoluminescence (PL) at room temperature in the as-synthesized transition metal dichalcogenide (TMD) ternary compound. The compositional and structural characterization studies of the materials are performed using XRD, SEM, EDX, TEM and Raman spectroscopy. We have observed that a combination of W and S leads to better crystallinity than the combination of Mo and S in the compound system. The high band gap (BG) energy also confirms the nanoscale dimension of the material system which may be attributed to the formation of excitonic states from spin splitting and band nesting effects. A theoretical investigation of the effect of W in the MoS2 system using DFT also reveals that insertion of W leads the system toward a direct BG semiconductor (SC). Multiple BGs of the material in the visible light range as found by UV–Visible (UV–Vis) spectroscopy, suggest applicability of these materials in luminescence devices and photocatalytic activity.

15 illus, 12 tables, 39 ref

002661   PRAMANIK A, BISWAS S, PAL S, SARKAR P (Chemistry Dep, Visva-Bharati Univ, Santiniketan 731 235, Email: pranab.sarkar@visva-bharati.ac.in) : Charge transport and transfer phenomena involving conjugated acenes and heteroacenes. Bull Mater Sci 2019, 42(3), 128.

Conjugated acenes are very promising for their applicability in different optoelectronic devices. In particular, pentacene (PCn) shows some distinct behaviours, namely high optical absorption and remarkably high carrier mobility which makes it as a landmark semiconductor for use in field-effect transistors or hole transporting materials in organic photovoltaics. During the last few decades, a large number of theoretical and experimental researches has been performed showing the practical applicability of different acenes and heteroatom-doped acenes (heteroacenes). Few reviews are also made in this regard. However, correlating the molecular properties arising from their intrinsic electronic structures with their charge transfer (CT) and transport characteristics is really scattered. Furthermore, very recent understandings on the nanojunctions made of acenes along with suitable electrodes need to be reviewed for further development of their performances in electronic devices. At the same time, the photovoltaic applicability of acenes and heteroacenes has recently been shown as an interplay of the dynamics of CT states as well as the intrinsic charge separation within the molecules or composites. The present review aims to point out those recent observations so as to draw more attention for further development in the area of aceneand heteroacene-based optoelectronic devices. We concentrate more on the structure–property relationships which could guide the device performance. As the subject area is so vast, we put emphasis on the very recent studies on PCn and some lower S,N-heteroacenes.

15 illus, 3 tables, 194 ref

002669   SINTHIYA M M A, KUMARESAN N, RAMAMURTHI K, SETHURAMAN K (Physics and Nanotechnology Dep, SRM Institute of Science and Technology, Kattankulathur 603203, Email: krmurthin@yahoo.co.in)) : Development of pure rutile TiO₂ and Magneli titanium sub-oxide microstructures over titanium oxide-seeded glass substrates using surfactant-free hydrothermal process. Bull Mater Sci 2019, 42(3), 127.

Titanium oxide seed layer was coated over glass substrates by sol–gel spin coating method. Single-step surfactant-free hydrothermal process developed titanium oxide microstructures over the titanium oxide-seeded glass substrates. Various morphologies of titanium oxide microstructures, varying from coral reefs to flower-like morphology were evolved by changing HCl concentration (1 and 3 M) in the precursor solution and growth temperature (GT) (120, 150 and 180^◦C) of the hydrothermal process. Structural studies confirmed the formation of rutile TiO₂, TiO₂ + Ti₂O₃ and Ti₄O₇ microstructures due to varying the concentration of HCl (1 and 3 M) in the solution and GTs. Morphological studies revealed the possibility of engineering coral reefs, cauliflower, flowers, ball, cactus and jasmine flower-shaped microstructures of titanium oxide films by tuning the growth parameters. The indirect band gap of the titanium oxide microstructures derived from UV–Vis absorption spectra lies in the range of 2.9–3.02 eV.

5 illus, 1 table, 40 ref

002672   SUASMORO S, WATI F A R, MUHAIMIN N (Physics Dep, Institute of Technology ‘Sepuluh Nopember’ Surabaya, Surabaya 60111, Indonesia, Email: suasm@its.ac.id) : Ti–Zr coating on graphite through powder immersion reaction-assisted coating (PIRAC) and its oxidation kinetics at T = 1000^◦ C. Bull Mater Sci 2019, 42(3), 126.

Coating of graphite with a metal alloy Ti–Zr was carried out on a block of graphite sample; the sample was initially dipped in ZrO₂ containing a natural starch solution and then proceeded to powder immersion reaction-assisted coating (PIRAC) after drying. Ti powder containing 4 wt% iodine was used as depositing material, and the process was carried out at 850−950^◦C for 10 h. The characterizations include X-ray diffraction, scanning electron microscopy and the hardness test. The coating thickness is proportional to the temperature of the PIRAC process, while the percentage of Zr is inversely proportional to the temperature of PIRAC treatment. All the characterizations revealed that the coated layer was a Ti–Zr alloy with hexagonal crystalline symmetry similar to α -Ti. An oxidation kinetic assessment at 1000^◦C of uncoated graphite shows a burns-off mechanism, while for a coated sample reveals a reaction of Ti with oxygen produces TiO₂; the reaction kinetics obey a diffusional mechanism.

7 illus, 2 tables, 17 ref

002649   KUMAR N B R, CRASTA V, PRAVEEN B M, SHETTY B G (Physics Dep, A J Institute of Engineering and Technology, Mangalore - 575 006, Email: rithin4u@rediffmail.com) : A conductive mechanism of PVA (Mowiol 10-98) filled with ZnO and MWCNT nanoparticles. Bull Mater Sci 2019, 42(3), 124.

Polyvinyl alcohol (PVA) hybrid nanocomposites are prepared via an ex situ approach with ZnO and MWCNT nanoparticle fillers and their conductive mechanisms have been investigated. The tailored hybrid nanocomposite conformation and their microstructural disparities for different filler concentrations were studied using an X-ray diffractometer. The direct current (DC) conductivity studies show an increase in the conductivity from 1.0528×10⁻¹¹ to 2.1514×10⁻⁸ S cm⁻¹ up to a percolation threshold filler concentration of x = 7.5 wt%. The dielectric constant substantially indicates a decreasing trend with increasing frequency. The exaggerated dielectric constant values of 11.8 at 5 kHz, 6.3 at 100 kHz, 5.86 at 500 kHz and 2 at 1 MHz are observed for 7.5 wt% filler hybrid nanocomposites, which indicate their potential application as a gate material in metal-oxide-semiconductor field-effect transistors (MOSFETs). The alternating current (AC) electrical conductivity demonstrates an increasing behaviour up to x = 7.5 wt% filler concentration. The smaller values observed in the real part of the electric modulus (M') indicates a riddance in electrode polarization. The observed higher frequency shift in the imaginary part of the electric modulus for increasing the filler concentration up to x = 7.5 wt%, decreases the relaxation time of the dipole orientation thereby increasing the conductivity mechanism of the hybrid nanocomposites. Apart from these, its small relaxation time with high electrical conductivity favours this material PVA/(x)MWCNT(15 − x)ZnO to have prospective application in microwave absorption appliances. The increase in the surface roughness of the film seen from the AFM images up to x = 7.5 wt% concentration supports an enhancement in the crystalline nature of the filler. Differential scanning calorimeter studies show an enhancement in glass transition temperature (T_g), melting temperature (T_m) and decomposition temperature (T_d) for PVA filled with MWCNTs and ZnO composites for optimum filler concentration x = 7.5 wt%.

8 illus, 2 tables, 36 ref

002621   BASHEER M A, PRASAD G, KUMAR G S, PRASAD N V (Physics Dep, Osmania Univ, Hyderabad 500007, Email: nvp1969@rediffmail.com) : Dielectric studies on Sm-modified two-layered BLSF ceramics. Bull Mater Sci 2019, 42(3), 114.

Sm_xBi_3−xTiNbO₉ (SBTN) with x = 0, 0.2, 0.4, 0.6, 0.8 and 1.0, a novel type of ceramic was prepared by a conventional solid-state reaction method. X-ray diffraction patterns confirm the formation of a single-phase, and lattice parameters were calculated based on the parent compound Bi3TiNbO9 (BTN). Well-defined grains were seen in the scanning electron microscopy pictures. A kink observed near 400^◦C for all the samples in the dielectric plot as well as in the stretched exponential parameter (β) vs. temperature plot reveals the dielectric relaxation of the samples. The tolerance factor (t) was found to increase with increase in the size of the A-site (Bi-site) modified ion (Sm). Impedance and modulus spectroscopic studies were conducted to understand the plausible reason for the dielectric relaxation. The relaxation was found to be well-fit with Arrhenius equation. SBTN samples showed lower dielectric loss compared to BTN. The remnant polarization, obtained from experimental, was found to be less than that of theoretically calculated polarization, using Shimakawa’s formula. The proposed defect mechanism was interpreted using FTIR and Raman spectroscopic studies.

8 illus, 1 table, 26 ref

002662   RASTOGI A, RAJPOOT P, VERMA U P (Jiwaji Univ, Gwalior 474001, Email: upv.udai@gmail.com) : Properties of group III–V semiconductor: BAs. Bull Mater Sci 2019, 42(3), 112.

The structural, electronic, mechanical, thermal and optical properties of boron arsenide (BAs) semiconductor, which belongs to group III–V, has been studied using the first-principles approach. BAs is a binary semiconductor compound, which has a space group F-43 m at ambient temperature. The structural and electronic properties of BAs are found to be in good agreement with the available experimental and theoretical results. Some of the mechanical properties are also in agreement with the data available. The thermal parameters such as Debye temperature, specific heat and Grüneisen parameter are analysed as functions of temperature and pressure.

5 illus, 3 tables, 66 ref

002618   ARULANANTHAM A M S, VALANARASU S, JEYADHEEPAN K, KATHALINGAM A (Physics Dep, Arul Anandar Coll, Karumathur 625514, Email: amsarul@gmail.com) : Effect of carrier gas pressure on structural, optical and photovoltaic properties of tin sulphide thin films prepared by nebulizer spray pyrolysis method. Bull Mater Sci 2019, 42(3), 100.

Tin sulphide (SnS) thin films deposited using nebulizer spray pyrolysis technique by changing pressure (0.1, 0.15, 0.2 and 0.25 Pascal) at 350◦C and their characterization are reported. The influence of carrier gas pressure on structural, morphological, optical and electrical properties of the film are determined using X-ray diffraction (XRD), energy-dispersive X-ray, atomic force microscopy, UV–Vis spectrophotometry and Hall effect measurement. Structural parameters such as pole density, orientation factor, crystallite size, micro strain and dislocation density were analysed using XRD data. The scanning electron microscopy studies display superior morphology and surface roughness of the films which were found to increase with pressure. Optical studies on the films revealed a variation in band gap from 1.78 to 1.66 eV for were the raise of pressure from 0.1 to 0.2 Pa. A single strong emission peak at about 825 nm is observed in photoluminescence spectra with enhanced intensity which may be attributed to near band edge emission. Grown SnS thin film exhibits p-type conductivity, which was confirmed from the Hall effect measurement. The low resistivity and higher carrier concentration are found to be 0.235 cm and 5.04 × 10¹⁸ cm⁻³, respectively. These properties were then correlated with the deposition parameters. Furthermore, to study the photovoltaic properties of SnS thin films, a heterojunction solar cell FTO/n-CdS/p-SnS/Al was fabricated showing conversion efficiency of 0.16 %.

11 illus, 4 tables, 47 ref

002655   MANDAL P, CHOWDHURY S, GHOSH S (Physics Dep, St. Xavier’s Coll, Mother Teresa Sarani, Kolkata 700016, Email: subhankar@sxccal.edu) : Spectroscopic characterization of Er³⁺ doped lead zinc phosphate glass via Judd–Ofelt analysis. Bull Mater Sci 2019, 42(3), 99.

Lead zinc phosphate (LZP) glass doped with 0.6% Er³⁺ is prepared by a conventional melt quenching technique. Judd–Ofelt (JO) analysis is carried out with an absorption spectrum of the as-prepared glass generating the set of JO parameters: Ω2 = 2.75 × 10⁻²⁰ cm⁻², Ω4 = 2.71 × 10⁻²⁰ cm⁻² and Ω6 = 0.44 × 10⁻²⁰ cm⁻². The magnitude of the spectroscopic quality factor (χp) defined by Ω4/Ω6 obtained in our sample turns out to be 6.16 which is 2–10 times larger than that of other Er³⁺ doped glasses. The lifetime of ⁴I_13/2 and ⁴I_11/2 levels estimated via the JO parameters is found to provide superior values of 7.25 and 5.51 ms, respectively. The elevated value of Ω4/Ω6 along with the estimated 100% luminescence branching ratio of ⁴I_13/2 →⁴I_15/2 transition implies that Er³⁺ doped LZP can be a promising material as a laser active medium.

2 illus, 3 tables, 40 ref

002636   HOLANDA R R, SANTOS D F, SILVA T G D D, BABU S, SANTANA C C, SOUZA W J (Physics Dep, Koneru Lakshmaiah Education Foundation, Guntur 522 502, Andhra Pradesh, Email: babu.computers@gmail.com) : Molecular dynamics of acetate-based ionic liquids. Bull Mater Sci 2019, 42(3), 94.

A radial distribution analysis of pairs between the constituent atoms of protic ionic 2-(hydroxy)ethylammonium acetate was performed with molecular dynamics technique (MDT). The ionic liquid structure will help us in different engineering applications, as emulsification process (petroleum industry). The results presented here show that the development of force field to predict the high interaction behaviour between the cation and the anion, as well as the formation of ion-pair dispersed aggregates. These results can contribute to help the different applications of ionic liquids.

2 tables, 10 ref

002627   DHOLEY S (Mathematics Dep, Maharajadhiraj Uday Chand Women’s Coll, Burdwan - 713 104, Email: sdholey@gmail.com) : Flow due to an infinite flat plate suddenly set into motion in a viscoelastic fluid: First stokes problem. Sadhana 2019, 44(5), 118.

The problem of flow and heat transfer due to an infinite flat surface suddenly set into motion in an unbounded mass of viscoelastic fluid is investigated under the consideration of time-dependent temperature distribution along the plate surface. A new type of similarity solution is devised that converts the governing partial differential equations into a set of non-linear ordinary differential equations with four physical parameters, viz., viscoelastic parameter k, unsteadiness parameter β, Eckert number E and Prandtl number Pr. These equations are then solved numerically by finite-difference method after using the perturbation technique owing to the inherent unavailability of the necessary boundary conditions for solving this type of flow problem. The influences of these parameters on this flow dynamics are graphically analysed. The present analysis discloses that both the velocity and temperature at a given location decrease with the increase of the elasticity in the fluid as well as the unsteadiness of the flow field. The analysis reveals that the elastic property of the fluids causes the back-flow inside the boundary layer after a certain value of the unsteadiness parameter depending upon the presence of elasticity in the fluids. Another important result of this study that comes from the heat transfer analysis is that the elasticity of the fluids reduces the severity of the unwanted effect of the viscous heating.

12 illus, 32 ref

002626   CHEN Z, YUAN X, WANG X, YUAN Y (China Three Gorges Univ, Yichang- 443 002, Email: yxh71@163.com) : Parameter estimation of chaotic systems based on extreme value points. Pramana– J Phys 2019, 92(6), 97.

Parameter estimation and synchronisation of chaotic systems are one of the hottest topics in the field of nonlinear science. In this paper, we addressed how to utilise the obtained experimental time series to estimate multiple parameters in chaotic systems. On the basis of relations of critical points and extreme value points, as well as the least squares estimation, we deduced a novel statistical parameter estimation corollary method to evaluate the unknown parameters in chaotic systems. In order to illustrate the feasibility and effectiveness of the proposed method, three numerical simulation results are presented, where the validity of the proposed method is verified in detail. Furthermore, we also investigated the effects of time-series noise and system disturbances for the proposed method, and the results showed that the proposed method is robust to uncertainties.

9 illus, 9 tables, 25 ref

002677   ZAYED E M E, AL-NOWEHY A-G, ELSHATER M E M (Mathematics Dep, Taiz Univ, Taiz, Yemen, Email: alnowehy2010@yahoo.com) : Solitons and other solutions for coupled nonlinear schrödinger equations using three different techniques. Pramana– J Phys 2019, 92(6), 96.

In this paper, we apply three different techniques, namely, the sine–cosine method, the new extended auxiliary equation method and the modified simple equation method for constructing many new exact solutions with parameters as well as bright–dark, singular and other soliton solutions of the coupled nonlinear Schrödinger equations. The solutions of these coupled nonlinear equations are compared with the well-known results.

6 illus, 53 ref

002632   EREMIN D A, GRISHANOV E N, POPOV I Y, BOITSEV A A (Higher Mathematics Dep, ITMO Univ, St. Petersburg- 197 101, Russia, Email: popov1955@gmail.com) : Model of tunnelling through quantum dot and spin–orbit interaction. Pramana– J Phys 2019, 92(6), 95.

Solvable mathematical model is suggested for tunnelling through quantum dot. The model is based on the theory of self-adjoint extensions of symmetric operators. The spin–orbit interaction is taken into account. The transmission coefficient is obtained. The result is compared with the case where spin–orbit interaction is absent.

3 illus, 28 ref

002634   GHOSH S, MUKHOPADHYAY S (Mathematics Dep, Burdwan Univ, Burdwan- 713 104, Email: swati_bumath@yahoo.co.in) : Effects of slip on Cu–water or Fe₃O₄–water nanofluid flow over an exponentially stretched sheet. Pramana– J Phys 2019, 92(6), 93.

This study aims to report the boundary layer flow of nanofluid over an exponentially stretched sheet in the presence of velocity slip as well as thermal slip. Utilising similarity transformations, the governing momentum and temperature equations are converted into ordinary differential equations and then solved numerically by shooting technique. An interesting behaviour of the solution for the converted self-similar equations is noted: dual solutions are obtained for some particular range of values of the governing parameters for the flow past an extended sheet. A comparison is made between the boundary layer flow of Cu–water and Fe₃O₄–water nanofluids. Both fluid velocity and temperature increase due to the enhancement in the velocity slip parameter. With the rising values of solid volume fraction, velocity diminishes but temperature increases.

6 illus, 1 table, 36 ref

002657   MOATIMID G M, MOHAMED M A A, HASSAN M A, EL-DAKDOKY E M M (Mathematics Dep, Ain Shams Univ, Cairo, Egypt, Email: mah371@yahoo.com) : Electro-osmotic flow and heat transfer of a non-Newtonian nanofluid under the influence of peristalsis. Pramana– J Phys 2019, 92(6), 90.

This paper investigates the electro-osmotic flow of non-Newtonian nanofluid through a peristaltic microchannel by considering the influence of electro-osmotic phenomenon. The effects of the Brownian and thermophoresis parameters are taken into account. The problem is modulated and its governing equations are solved analytically by assuming long wavelength and low Reynolds number. The distributions of the axial velocity, temperature, nanoparticles volume fraction and volumetric flow rate are achieved and plotted under the influence of various parameters. In addition, the expressions for the skin friction, Nusselt number and Sherwood number are obtained and illustrated through a set of graphs. Furthermore, the trapping phenomenon is examined with the Rayleigh, Brownian and thermophoresis parameters. The present results are useful in medical and biological applications, especially in cancer therapy, which involves suspended nanoparticles of gold in blood (nanofluid) passing through a peristaltic tube (artery).

12 illus, 1 table, 31 ref

002675   YANG Z, NING L (Shaanxi Normal Univ, Xi’an- 710 119, China, Email: ninglijuan@snnu.edu.cn) : Vibrational resonance in a harmonically trapped potential system with time delay. Pramana– J Phys 2019, 92(6), 89.

This paper is focussed on investigating the effect of linear time delay on vibrational resonance of a harmonically trapped potential system driven by a biharmonic external force with two wildly different frequencies ω and Ω with ω << Ω. Firstly, the approximate analytical expression of the response amplitude Q at the lowfrequency ω is obtained by means of the direct separation of the slow and fast motions, and then we verified the numerical simulation by using the fourth-order Runge–Kutta method and found that it is in good agreement with the theoretical analysis. Next, the influence of the time-delay parameters on the vibrational resonance are discussed. There are some meaningful conclusions. If τ is a controllable parameter, the response amplitude Q not only exhibits periodicity but also can be amplified via the cooperation of F and τ . If the time-delay intensity parameter r is a controllable parameter, the response amplitude Q is found to be much larger than that in the absence of time delay. Moreover, adjusting r can result in a better response than adjusting τ . This undoubtedly gives us a superior way to amplify the weak low-frequency signal.

14 illus, 25 ref

002673   SUMESH C K, PAREKH K (Physical Sciences Dep, P D Patel Institute of Applied Sciences, Changa- 388 421, Email: cksumesh.cv@charusat.ac.in) : Nanocatalytic physicochemical adsorption and degradation of organic dyes. Pramana– J Phys 2019, 92(6), 87.

Physicochemical adsorption and degradation of the azo dye, methylene blue (MB), when irradiated by visible and UV light in aqueous ZnO suspension have been investigated. The novelty of this work is to investigate the effect of dye concentration up to 200 mg/l, keeping the nanocatalysts’ concentration invariant as 1 g/l. The nanocatalysts before and after degradation process have been analysed to understand the mechanism of dye removal using X-ray diffractometer (XRD), Fourier-transform infrared spectroscopy (FTIR) and thermal gravimetric analyser (TGA). The results show that UV light degrades the dye to its intermediates through chemi-adsorption, whereas the visible light induces physisorption of dye molecules on ZnO nanocatalysts. The XRD pattern of the ZnO nanocatalysts revealed no changes in the internal structure of ZnO after the degradation process, confirming the reuse of catalysts.

13 illus, 1 table, 26 ref

002647   KHALID M, ATA-UR-RAHMAN, HADI F, ZEB A (Physics Dep, Islamia Coll, Peshawar- 25120, Pakistan, Email: ata797@yahoo.com) : Nonlinear ion flux caused by dust ion-acoustic nonlinear periodic waves in non-thermal plasmas. Pramana– J Phys 2019, 92(6), 86.

The propagation of dust ion-acoustic nonlinear periodic (cnoidal) waves is investigated in an unmagnetised dusty plasma characterised by a non-thermal electron population. The equations describing the dynamics of the wave potential in the first and second orders of perturbation theory are derived, and their nonsecular periodic solutions are found. The average nonlinear ion flux caused by the propagation of a cnoidal wave is determined. The nonlinear ion flux is found to depend significantly on dust concentration and non-thermality parameter.

2 illus, 33 ref

002624   CHAKRABORTY P K, MONDAL B N, CHAUDHURI B K (Jadavpur Univ, Kolkata- 700 032, Email: sspbkc@rediffmail.com) : Laser-induced modulation of optical band-gap parameters in the III–V-type semiconductors from the density-of-state (DOS) calculations. Pramana– J Phys 2019, 92(6), 85.

Optical band gap (E_g0) is a parameter of paramount importance in describing various transport and optoelectronic properties of the III–V-type low band-gap semiconductors. In the present communication, an attempt has been made to develop an energy–momentum (E−k¯) dispersion relation for studying the density-of-state (DOS) and band-gap-related parameters. The external laser excitation has been treated as a perturbation. It has been shown theoretically that due to such excitation with different intensity (I) and wavelength (λ), the band edge of the conduction band (CB) of the III–V compound semiconductors moves vertically upward, indicating laser modulation (increase) of Eg0 and related parameters compared to those of the normal ones (unperturbed). Therefore, in the presence of light, the original CB edge forms a pseudo-CB edge above the unperturbed CB edge in the forbidden band (FB) zone. This new development of the (E−k¯) relationship has also been extended for the estimation of exact optical effective mass (OPEM) of an electron in some III–V compound semiconductors. The OPEM variation with carrier concentration showed a continuous decreasing nature, while the corresponding variation of electron effective mass (EEM) (without laser excitation) exhibited an increasing trend. The present theoretical results would be important for the deeper understanding of the variation of OPEM with I and λ. The observed new results will also be beneficial for studying laser-induced effects in semiconductor heterostructures with different applications in optoelectronic devices.

10 illus, 3 tables, 34 ref

002638   JONG C, RI B-I, YU G-D, KIM S-G, JO S-I, JON S-H (Kim Chaek Univ of Technology, Pyongyang, Democratic People’s Republic of Korea, Email: jch59611@star-co.net.kp) : Ensemble in phase space: Statistical formalism of quantum mechanics. Pramana– J Phys 2019, 92(5), 83.

We present an alternative formalism of quantum mechanics tailored to statistical ensemble in phase space. The purpose of our work is to show that it is possible to establish an alternative autonomous formalism of quantum mechanics in phase space using statistical methodology. The adopted perspective leads to obtaining within the framework of its theory the fundamental quantum-mechanical equation without recourse to the other formulations of quantum mechanics, and gives the idea for operators pertaining to dynamical quantities. The derivation of this equation starts with the ensemble in phase space and, as a result, reproduces Liouville’s theorem and virial theorem for quantum mechanics. We have explained with the help of this equation the structure of quantum mechanics in phase space and the approximation to the Schrödinger equation. Furthermore, we have shown that this formalism provides reasonable results of quantisation such as the quantisation of harmonic oscillation, the two-slit interference and the uncertainty relation. In particular, we have demonstrated that this formalism can easily give the relativistic wave equation without using the linearisation of the Hamiltonian operator. The ultimate outcome this formalism produces is that primary and general matters of quantum mechanics can be studied reasonably within the framework of statistical mechanics.

3 illus, 66 ref

002674   SWAPNA M S, DEVI H V S, AMBADAS G, SANKARARAMAN S (Optoelectronics and Nanoscience and Nanotechnology Dep, Kerala Univ, Thiruvananthapuram- 695 581, Email: drssraman@gmail.com) : Tunable fluorescence from natural carbon source: Pandanus. Pramana– J Phys 2019, 92(5), 80.

Carbon materials possessing photoluminescence properties are considered as potential candidates in a wide range of photonic and optoelectronic applications. In this work, the cellulose derived from the natural source, Pandanus, is autoclave-treated for the synthesis of fluorescent carbon. The natural fibres are greatly preferred over synthetic ones due to their cost-effectiveness, easy processability, non-abrasivity, non-toxic and environmentfriendly characteristics along with high mechanical strength and damage tolerance. These properties enable them to be used as templates for synthesis, as important reinforcement materials for commercial thermoplastics and for making value-added products. In this study, the synthesised sample is subjected to structural, morphological, elemental and optical characterisations. These studies reveal that the sample can be used as a low-cost tunable light-emitting source for photonic, biomedical and biosensing applications.

8 illus, 2 tables, 34 ref

002663   RAUSHAN R, SHUKLA A K, CHAUBEY R, SINGH T (Banaras Hindu Univ, Varanasi- 221 005, Email: yahoo_raghav@rediffmail.com) : Locally rotationally symmetric Bianchi type-I cosmological model with dynamical Λ and G in f(R) gravity. Pramana– J Phys 2019, 92(5), 79.

In this paper, we have studied the locally rotationally symmetric (LRS) Bianchi type-I cosmological model filled with a bulk viscous cosmological fluid in f(R) gravity in the presence of time-varying gravitational and cosmological constant. We have used the power-law and intermediate scenario for scale factor to obtain the solution of the field equations. The evolution of temperature of a viscous Universe is also analysed.

12 illus, 62 ref

002671   SREERAJ T, SINGH S V, LAKHINA G S (Indian Institute of Geomagnetism, Navi Mumbai- 410 218, Email: sreerajt90@gmail.com) : Higher harmonic instability of electrostatic ion cyclotron waves. Pramana– J Phys 2019, 92(5), 78.

Electrostatic ion cyclotron instability pertaining to the higher harmonics of proton and helium cyclotron modes is investigated in three-component magnetised plasma consisting of beam electrons, protons and doubly charged helium ions. The effect of different plasma parameters, namely, angle of propagation, number density and temperature of helium ions and electron beam speed, has been studied on the growth of proton and helium cyclotron harmonics. It is found that an increase in angle of propagation leads to the excitation of fewer harmonics of proton cyclotron waves with decreased growth rates and higher number of helium harmonics with decreased growth rates. Also, largely odd helium harmonics are excited, except for one particular case where the second harmonic also becomes unstable. The number density and temperature of ions have significant effect on the helium cyclotron instability compared to the proton cyclotron instability. Further, as the speed of electron beam is increased, the peak growth rate increases. Our results are relevant to laboratory and space plasmas where field-aligned currents exist.

6 illus, 47 ref

002660   OJO K S, ADELAKUN A O, OLUYINKA A A (Physics Dep, Federal Univ of Technology, Ondo state, Nigeria, Email: aoadelakun@futa.edu.ng) : Synchronisation of cyclic coupled Josephson junctions and its microcontroller-based implementation. Pramana– J Phys 2019, 92(5), 77.

Based on Routh–Hurwitz criterion, this paper reports on synchronisation of two coupled 3D Josephson junctions via cyclic coupling. Analytical conditions which lead to stable synchronisation through the cyclic coupling were derived. Numerical and microcontroller-based circuit simulations are employed to verify the feasibility and effectiveness of the derived analytical criteria. The cyclic coupling has potential applications in neural information transmission and communication in natural systems.

4 illus, 31 ref

002623   BHOWMICK A, KARA D, MOHAPATRA A K (National Institute of Science Education and Research Bhubaneswar, Khurda- 752 050, Email: arup.b@niser.ac.in) : High-sensitivity measurement of Rydberg population via two-photon excitation in atomic vapour using optical heterodyne detection technique. Pramana– J Phys 2019, 92(5), 76.

We demonstrate a technique based on optical heterodyne detection to measure the Rydberg population in the thermal atomic vapour. The technique used a probe beam far off-resonant to the D2 line of rubidium along with a reference beam with frequency offset by 800 MHz in the presence of a coupling laser that couples to Rydberg state via two-photon resonance. The polarisation of the probe, reference and coupling beams are suitably chosen such that only the probe beam goes through a nonlinear phase shift due to the two-photon process which is measured relative to the phase shift of the reference beam using optical heterodyne detection technique. We show that the technique has a sensitivity to measure the minimum phase shift of the order of a few μrad. We have used a suitable model of two-photon excitation of a three-level atom to show that the minimum phase shift measured in our experiment corresponds to the Rydberg population of the order of 10⁻⁵. The corresponding probe absorption for the given laser parameters is of the order of 10⁻⁷. We demonstrate that this technique is insensitive to polarisation impurity or fluctuations in the beams. The technique is particularly useful in measuring the Rydberg population via two-photon excitation in thermal vapour where microchannel plates (MCP) could be relatively difficult to implement. It can also be used in the ultracold atomic sample with suitable laser parameters.

5 illus, 56 ref

002664   SALMAN S M (Mathematics Dep, Alexandria Univ, Alexandria, Egypt, Email: samastars9@alexu.edu.eg) : Long-term dynamics of a q-deformed discrete susceptible–infected–susceptible epidemic model with delay. Pramana– J Phys 2019, 92(5), 74.

The main thrust of this paper is to consider a delayed q-deformed discrete susceptible–infected– susceptible (SIS) epidemic model. Parametric conditions on the local stability of the disease-free fixed point and the endemic fixed points are obtained. A codimension-one bifurcation analysis at the fixed points of the model is discussed. The model has a variety of bifurcations such as flip, transcritical, and pitchfork bifurcations. Numerical simulations including trajectories, bifurcation diagrams, maximal Lyapunov exponent, and phase portraits are illustrated to verify the obtained analytical results. It has been noticed that introducing the delay in the absence of deformations recovers the chaotic behaviour of the model. Meanwhile, introducing both deformations and delay suppress the chaotic behaviour of the model. The disease will be eradicated by increasing the value of both deformation and delay strength parameters.

8 illus, 22 ref

002644   KASHYAP K P, OJJELA O, DAS S K (Applied Mathematics Dep, Defence Institute of Advanced Technology (Deemed Univ), Pune - 411 025, Email: odelu@diat.ac.in) : Magnetohydrodynamic mixed convective flow of an upper convected Maxwell fluid through variably permeable dilating channel with Soret effect. Pramana– J Phys 2019, 92(5), 73.

The effects of Soret and variable porosity on an unsteady magnetohydrodynamic flow of an upper convected Maxwell fluid through an expanding or contracting channel are explored in this article. The temperature and concentration at the walls are maintained at different values. The gravitational forces arising from temperature and concentration gradients are also considered. The behaviour of velocity components, skin friction, temperature and concentration with respect to various non-dimensional parameters has been numerically computed by using an efficient shooting method. Newtonian case has been studied using the current algorithm and the present results are compared with earlier literature. At the boundaries, the heat and mass transfer rates are studied using local Nusselt and Sherwood numbers. The results show that both the variable permeability and wall expansion have dominant effects on skin friction at the plates. The Prandtl and Soret numbers have dominating effect on mass transfer when compared with variable permeable parameter.

7 illus, 1 table, 49 ref

002619   BAKHODAY-PASKYABI M, VALINEJAD A, AZODI H D (Nansen Environmental and Remote Sensing Center, Bergen, Norway, Email: Mostafa.Bakhoday@nersc.no) : Numerical solution of regularised long ocean waves using periodised scaling functions. Pramana– J Phys 2019, 92(5), 71.

In this paper, a numerical technique for solving the regularised long wave equation (RLW) is presented using a wavelet Galerkin (WG) method in space and a fourth-order Runge–Kutta (RK) technique in time. We study the convergence analysis of the obtained numerical solutions and investigate the results for the motions of double and single solitary waves, undular bores and conservation properties of mass, energy and momentum in order to verify the applicability and performance of the proposed method. Simulation results are further compared with the known analytical solutions and some previous published numerical results. It is concluded that the present method remarkably improves the accuracy of the Galerkin-based methods for numerically solving a large class of nonlinear and weakly dispersive ocean waves.

10 illus, 9 tables, 36 ref

002635   GUPTA R K, SINGH M (Punjabi Univ, Sabo- 151 302, Email: manjitcsir@gmail.com) : On invariant analysis and conservation laws for degenerate coupled multi-KdV equations for multiplicity l=3. Pramana– J Phys 2019, 92(5), 70.

The degenerate coupled multi-Korteweg–de Vries equations for coupled multiplicity l=3 are studied. The equations, also known as three-field Kaup–Boussinesq equations, are considered for invariant analysis and conservation laws. The classical Lie’s symmetry method is used to analyse the symmetries of equations. Based on the Killing’s form, which is invariant of adjoint action, the full classification for Lie algebra is presented. Further, one-dimensional optimal group classification is used to obtain invariant solutions. Besides this, using general theorem proved by Ibragimov, we find several non-local conservation laws for these equations. The conserved currents obtained in this work can be useful for the better understanding of some physical phenomena modelled by the underlying equations.

41 ref

002668   SINGH S S, SAXENA G (Physics and Astrophysics Dep, Delhi Univ, Delhi- 110 007, Email: sssingh@physics.du.ac.in) : Effect of two-loop correction in the formation of quark–gluon plasma droplet. Pramana– J Phys 2019, 92(5), 69.

The effect of two-loop correction in quark–gluon plasma (QGP) droplet formation is studied by introducing the two-loop correction factor in the mean-field potential. The correction factor leads to the stability in the droplet formations of QGP at different parametrisation factors of the QGP fluid. This also shows that the gluon parameter factor shifts to a larger value from its earlier value of one-loop correction in attaining the stability of the droplets. The results show a decrease in the observable QGP droplet sizes which are found to be 1.5–2.0 fm radii with the two-loop correction. It indicates that the dynamics of the QGP droplet and the stability of the droplet with the two-loop correction factor can be controlled by the fluid parameter in the model.

7 illus, 39 ref

002631   EFTEKHARI-KENZERKI Z, FARDID R, BEHZAD-BEHBAHANI A (Radiology Dep, Shiraz Univ of Medical Sciences, Shiraz, Iran, Email: rfardid@sums.ac.ir) : Impact of silver nanoparticles on the ultraviolet radiation direct and bystander effects on TK6 cell line. J Med Phys 2019, 44(2), 118-25.

Ultraviolet C (UVC) radiation is harmful to cells and living organisms that cause direct and indirect DNA damage. UVC can also increase the inflammatory genes expression such as COX‑2 that results in elevated oxidative stress that plays a role in radiation‑induced bystander effect (BSE). Silver nanoparticles (AgNPs) have used widely in commercial and medical products and the toxicological risks of AgNPs must be determined. The aim of this study was to investigate the direct and BSEs of UVC radiation and AgNPs on TK6 cell line.  TK6 cells were exposed to AgNPs (10 µg/ml, 1 h). Then, they were exposed to UVC and to determine the BSEs of radiation, the irradiated cells media were transferred to nonirradiated cells. Expression level of H2AX and COX-2 mRNAs were examined by quantitative real-time PCR and 8-OHdG formation was examined by ELISA. The cell viability examined by MTT assay. P < 0.05 was considered as the level of significance. The results showed that the mean expression level of H2AX mRNA in the AgNPs + UVC group increased significantly in comparison with UVC group. 8‑OHdG increased significantly in the BSE of UV group in comparison with sham control of BSE. COX‑2 mRNA increased significantly in the BSE of AgNPs + UVC with sham control in BSE. Our findings showed the induced DNA damage in TK6 cell by AgNPs and UVC radiation and also were seen BSE.

8 illus, 2 tables, 43 ref

002670   SPYRATOU E, DILVOI M, PATATOUKAS G, PLATONI K, MAKROPOULOU M , EFSTATHOPOULOS E P (National and Kapodistrian Univ of Athens, Athens- 12462, Greece, Email: stathise@med.uoa.gr) : Probing the effects of ionizing radiation on young’s modulus of human erythrocytes cytoskeleton using atomic force microscopy. J Med Phys 2019, 44(2), 113-7.

In this work, we examined the possible effects of ionizing radiation (IR) on biomechanical properties of the membrane–cytoskeleton of human erythrocytes, after X‑ray irradiation. Whole human blood from three healthy middle‑aged volunteers was drawn by venipuncture and stored in tubes containing anticoagulant. Six blood samples were collected for each volunteer. Five of them were irradiated in the range of 0.1 Gy–2.0 Gy doses and one was used as control. The morphology and the elastic modulus of the erythrocytes were examined using atomic force microscopy and just few drops of whole blood. No morphological changes appeared according to the shape and the morphology of the erythrocytes. The elastic modulus of the irradiated samples was reduced with the increase of radiation dose. The findings indicate that X‑ray irradiation affects the biomechanical properties of erythrocyte cytoskeleton. The mean value of Young’s modulus of all the irradiated blood samples was significant difference from the control at a level, P < 0.01. The elastic modulus of the erythrocytes could be an indicator of the adverse effect in the human blood generated by IR exposure through a radiotherapy treatment.

5 illus, 31 ref

002630   EEDEN D V, PLESSIS F C P D (Medical Physics Dep, Free State Univ, Bloemfontein- 9300, South Africa, Email: VaneedenD@ufs.ac.za) : Multi-Energy computed tomography breast imaging with Monte Carlo simulations: Contrast to noise based image weighting. J Med Phys 2019, 44(2), 106-12.

Photon‑counting detectors and breast computed tomography imaging have been an active area of research. With these detectors, photons are assigned an equal weight and weighting schemes can be enabled. More weight can be assigned to lower energies, resulting in an increase in the contrast‑to‑noise ratio (CNR). The aim of this study is to develop and evaluate an energy weighting imaging technique to improve the CNR of simulated breast phantoms and to improve tumour detection. Breast phantoms consisting of adipose, glandular, malignant tissues and iodine contrast were constructed with Breast Simulator software. The phantoms were used in egs_cbct simulations for energies ranging between 20 and 65 keV from which multiple images were reconstructed. A new CNR‑based image weighting method was proposed based on the CNR values obtained from the images. This method improves on previous methods and can be applied to complicated phantoms since no structural information is needed. An increase in the CNR can be seen for lower energies. A sharp increase in the CNR is seen just above the K‑edge for the phantoms with the iodine contrast. The CNR‑based image weighting leads to a 68.47 % (1.68‑fold) increase in the CNR for the malignant tissue without iodine. For the malignant tissue with iodine contrast, the increase in the CNR was 96.14 % (1.96‑fold). The new proposed CNR‑based image weighting scheme is easy to implement and can be used for complicated phantoms with varying structures. A large increase in the CNR is seen with or without the use of iodine contrast.

12 illus, 48 ref

002625   CHAUDHARY R K, KUMAR R, SHARMA S D, BERA S, MITTAL V, DESHPANDE S (Radiological Physics and Advisory Div, Bhabha Atomic Research Centre, Anushakti Nagar- 400 094, Email: rahulchaudhary1986@yahoo.co.in) : Performance validation of in house developed four dimensional dynamic phantom. J Med Phys 2019, 44(2), 99-105.

The objective of this study was to validate the performance characteristics of in‑house developed four‑dimensional (4D) dynamic phantom (FDDP). There are three target inserts of 1.0, 1.5 and 2.0 cm diameter. The targets were driven in sinusoidal pattern in the longitudinal direction, using the combinations of amplitudes of 0.5, 1.0, and 1.5 cm with frequencies of 0.2 and 0.25 Hz.  The amplitude and frequency of motion were measured manually, and by using Real‑Time Position Management (RPM) system also. The static, free‑breathing, and 4D computed tomography (CT) scans of the phantom were acquired with 1.0 mm slice thickness.The 4DCT scans were sorted into 0 %–90 % phase, and the maximum intensity projection (MIP) images were also generated. The static, free‑breathing, and 4DCT data sets and MIP images were contoured to get V_Static, V_FB, V₀₀......V₉₀, and internal target volume ITV_MIP, respectively. The individual phase volumes were summed to obtain V_4D. The length of the target in the motion was measured using MIP image and compared with theoretical length (TL). The variation of 3D displacement vector of individual phase volume with respect to V₀₀ with the phase of motion was studied at amplitude and frequency of 1.0 cm and 0.25 Hz, respectively. The degree of similarity between V_FB and V_4D and V_FB and ITV_MIP was also studied for all the target sizes at amplitude and frequency of 1.0 cm and 0.2 Hz and 1.0 cm and 0.25 Hz, respectively. The amplitude and frequency of motion agreed within the limits of uncertainty with the manually and RPM measured values. The length of target in the motion matched within 1.0 mm with TL. The 3D displacement of individual phase volume showed no target size dependence, and the degree of similarity between V_FB and V_4D and V_FB and ITV_MIP decreases with increase in the displacement between the two volumes. The mechanical and imaging performances of FDDP were found within the acceptable limits. Therefore, this phantom can be used for quality assurance of 4D imaging process in radiotherapy.

10 illus, 2 tables, 30 ref

002656   MARKOVIC M, NARAYANASAMY G, STATHAKIS S, MAVROIDIS P, JURKOVIC I-A, SAENZ D, PAPANIKOLAOU N (Radiation Oncology Dep, Texas Health San Antonio Univ, Texas- 78229, Email: markovic@livemail.uthscsa.edu) : Clinical evaluation of a two dimensional liquid filled ion chamber detector array for verification of high modulation small fields in radiotherapy. J Med Phys 2019, 44(2), 91-8.

Clinical evaluation of a two‑dimensional (2D) liquid‑filled ion chamber detector array used in the verification of highly modulated small beams of stereotactic body radiation therapy (SBRT) has been conducted. Measurements with the Octavius 1000 SRS (PTW, Freiburg, Germany) detector with 977 liquid‑filled ion chambers were compared against EDR2 film and PTW Octavius Seven29. The performance of detector array has been evaluated on ten SBRT patient plans. Dose profiles of individual and composite fields’ calculated using Pinnacle³ treatment planning system were compared against measurements with Octavius 1000 SRS detector array, EDR2 film, and Octavius Seven29 detector. Gamma index and profile comparison were used in the evaluation and assessment of the detector’s performance. The Gamma index measurements show agreement between Pinnacle³ computations and Octavius 1000 SRS array, PTW Octavius Seven29, and EDR2 film for >90 % of the points using 2 %, 2 mm tolerance criteria. Profiles obtained with the Octavius 1000 SRS were in agreement with the EDR2 film profiles, demonstrating the detector’s superior sampling rate. The Octavius 1000 SRS is a dosimetrically accurate device to perform quality assurance checks in SBRT treatments. The broad range of measurements performed in this study quantified the dosimetric accuracy of Octavius 1000 SRS detector in the clinical setup of the small fields in radiotherapy.

7 illus, 2 tables, 30 ref

002665   SELVAN K T, PADMA G , REVATHY M K, RAJ N A N , SENTHILNATHAN K , BABU P B (Physics Dep, VIT Univ, Vellore, Tamil Nadu, Email: prameshbabu@vit.ac.in) : Dosimetric effect of rotational setup errors in single isocenter volumetric modulated arc therapy of multiple brain metastases. J Med Phys 2019, 44(2), 84-90.

The aim of this study is to investigate the dosimetric effects of rotational uncertainties in patient positioning on target coverage in stereotactic radiosurgery (SRS) of multiple brain metastases using single isocenter volumetric modulated arc therapy (VMAT). Ten SRS cases with multiple brain metastases (2-8) planned with single isocenter non-coplanar VMAT technique were investigated in this study. Pitch, yaw and roll displacements of 1, 3 and 5° were simulated about isocenter along each axes and nine plans were obtained for each case. Gross tumor volume (GTV) coverage obtained on simulated plans were compared with the original plan on four metrics of mean dose (Dmean), minimum dose to GTV (Dmin), dose to 95 % of GTV (D95) and the volume covered by the 95 % of the prescribed dose (V95). At 1° rotation about 4 % of the PTV had V95 and D95 values <95 %. The minimum dose obtained across all PTV was 85.1 % and there was not much change in the mean dose values obtained. The PTV volume which had V95 and D95 values <95 % were in the range of 0.05 - 0.07cc and at a radial distance of 6.2 cm - 7.2 cm. At 3° rotation almost 50 % of the PTV had V95 and D95 values <95 %. The minimum dose obtained across all PTV was 48.3 % and the mean dose reduced to as low as 78.8 %. At 5 ° rotation almost 74 % of the PTV had V95 and D95 values <95 %. The minimum dose obtained across all PTV was 21.2 % and the mean dose reduced to as low as 49.2 %. Our results indicate that correcting rotational uncertainties is critical in single-isocenter, multi-target SRS. For rotational deviations, radial distance of the target from isocenter along the respective axis has a strong influence on target coverage. For rotational setup deviation at a given radial distance larger targets tend to have lesser geometric miss compared to smaller targets. Mathematical model for spherical targets can be used to estimate V95 for given rotational errors.

8 illus, 1 table, 21 ref

002637   HOLLA R, KHANNA D, BARSING S, PILLAI B K, GANESH T (Physics Dep, Karunya Institute of Technology and Sciences, Coimbatore- 641 114, Email: davidkhanna@karunya.edu) : Investigation of internal target volumes using device and deviceless four dimensional respiratory monitoring systems for moving targets in four dimensional computed tomography acquisition. J Med Phys 2019, 44(2), 77-83.

The influence of target motion on the reconstructed internal target volume (ITV) for device-based (DB) external surrogate system and Smart deviceless (DL) 4-dimensional (4D) system were compared in a controlled phantom experiment. The volumetric changes in reconstructed ITVs from the average intensity projection (AveIP) images using DB method (Anzai Respiratory Gating System, ANZAI MEDICAL CO., LTD, Japan) and DL method (Smart deviceless 4D system by GE Medical Systems (Chicago, USA)) with the theoretical true volume (ITV_th) for moving target with the increasing target motion in anterior-posterior (A-P), lateral (left-right [L-R]) and inferior-superior (S-I) directions were assessed. 4D computed tomography (4DCT) of CIRS dynamic phantom (Computerized Imaging Reference Systems Inc., Norfolk, VA, USA) with 2.5 cm diameter spherical target of volume 8.2 cc programmed to move in a cos⁴ (x) motion pattern placed in the lung volume were acquired for various target motion pattern using DB and DL method of gating. AveIP images of 10 phase binned image sets were generated and ITVs were delineated. The maximum absolute percent differences between ITV_ave and ITV_th for DL and DB methods were 15.91 % and 4.94 % respectively for target motion of 5 mm in AP with 15 mm S-I direction. When the S-I motion was decreased to 10 mm, the observed % difference of the ITVs were also decreased to 12.5 % and 0.3 % for DL and DB method. When the lateral [L-R] motion was varied from 0 mm to 5 mm for S-I motion of 5 mm to 15 mm, the differences in the ITVs were significant (P = 0.004) with the maximum absolute percent difference of 18.61 % and 4.94 % for DL and DB gating. With the simultaneous motion of the target in all the 3 directions, the difference in the reconstructed ITVs were statistically significant for DL method (P = 0.0002) and insignificant for DB method (P = 0.06) with an average increase of 10 % in ITVDL against 2 % in the ITVDB. The difference in ITVDL was significant for the target motion above 3 mm in A-P and L-R directions for S-I movement of above 10 mm (P = 0.0002). However, for low excursions of the target movement, no significant difference in the ITVs were observed (P > 0.06). In general, ITVDBs were closer to the ITVth (within 7.8 %) than ITVDL (18.61 %). The results showed that the DL method is an effective way of image sorting in 4D acquisition for smaller target excursion. When the target motion exceeds 3 mm in A-P and L-R directions with S-I more than 10 mm, DB method is the choice due to its accuracy in reproducing the absolute target volume.

4 illus, 25 ref

001341   JOSEPH S, JETHVA H O, JOSHI M J (Physics Dep, Alphonsa Coll, Pala - 686 575) : Knoop micro-hardness studies on (110) surface of gel grown strontium tartrate di-hydrate crystal. Indian J Pure Appl Phys 2019, 57(4), 278-84.

The wedge shape or elongated pyramid Knoop indenter is preferred for micro-hardness anisotropy study. In the Knoop indenter, the width, volume or projected area of the indentation mark can be used as a measure of hardness by aligning the indenter along a particular direction of a surface. In the present study, the (110) surface of gel grown strontium tartrate di-hydrate crystal has been used for the Knoop micro-hardness study. The anisotropy of micro-hardness has been studied by changing the orientation of the Knoop indenter from 0º to 200º at a fixed load, which indicates one maximum and one minimum value of the Knoop micro-hardness. The variation of Knoop micro-hardness with applied load in the range of 5 g to 100 g load indicates three maxima of the Knoop micro-hardness values.

5 illus, 56 ref